This invention relates to a novel developer composition for photographic color negative films and to a method of development that provide rapid development and production of high quality color display images.
Production of photographic color images from light sensitive silver halide materials basically consists of two processes. First, color negative images are generated by light exposure and processing of camera speed, light sensitive films, that are sometimes called xe2x80x9coriginatingxe2x80x9d elements because the images are originated therein by the film user (that is, xe2x80x9cpicture takerxe2x80x9d). These negative images are then used to generate positive images in light sensitive materials. These latter materials are sometimes known as xe2x80x9cdisplayxe2x80x9d elements and the resulting images may be known as xe2x80x9cprintsxe2x80x9d when coated on reflective supports or xe2x80x9cfilmsxe2x80x9d when coated on nonreflective supports.
The light sensitive materials are processed in automated processing machines through several steps and processing solutions to provide the display images or prints. Traditionally, this service has required a day or more. In recent years, customers have wanted faster service, and in some locations, the time to deliver this service has been reduced to within an hour. Reducing the processing time to within a few minutes is the ultimate desire. To do this, each step must be shortened.
The photographic films processed in the practice of this invention are multilayer color elements having at least two color records. Such films typically contain dye image-forming units (or color records) sensitive to each of the three primary regions of the visible spectrum. Each unit can comprise a single silver halide emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. In an alternative format, the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer. The elements can also contain other conventional layers such as filter layers, interlayers, subbing layers, overcoats and other layers readily apparent to one skilled in the art. A magnetic backing can be used as well as conventional supports. Preferably, transparent supports are employed in the films as are well known in the art. The layers of the photographic films can have known binder materials, including various types of gelatins and other colloidal materials (or mixtures thereof).
Color negative films generally have little or no silver chloride in their emulsions, and have silver bromide as the predominant silver halide. More typically, the emulsions are silver bromoiodide emulsions with silver iodide levels up to several mol percent. Such films have required these types of emulsions because emulsions containing high silver chloride have generally had insufficient light sensitivity to be used as camera speed materials although they have the advantage of being rapidly processed without major changes to the color developer solution.
To shorten the processing time, specifically the color development time, of films containing silver bromoiodide emulsions, more active color developer solutions are needed. Various attempts have been made to increase color developer activity by increasing the pH, increasing the color developing agent concentration, decreasing the halide ion concentration, or increasing temperature. However, when these changes are made, the stability of the solution and the photographic image quality are often diminished.
For example, when the development temperature is increased from the conventional 37.8xc2x0 C., and the color developer solution is held (or used) in the processing tanks for extended periods of times, silver bromoiodide elements processed with such solutions often exhibit unacceptably high density in the unexposed areas of the elements, that is, unacceptably high Dmin.
U.S. Pat. No. 5,344,750 (Fujimoto et al) describes a method for processing films containing silver iodobromide emulsions that is allegedly rapid, including color development for 40-90 seconds. The potential problems of low sensitivity and high fog in rapidly developed films is asserted to be overcome by using a color development temperature and an amount of color developing agent and bromide ion in the color developer that are determined by certain mathematical relationships. That is, the amount of color developing agent and bromide ion are considered to be related, and the development temperature and bromide ion concentration are related, both relationships being expressed in mathematical equations.
It has been found, however, that even when the relationships described in U.S. Pat. No. 5,344,750 are followed and color negative films are color developed in short times (less than 90 seconds), the color balance of the three color records cannot be maintained through a useful exposure range. By xe2x80x9ccolor balancexe2x80x9d is meant the display image, produced from a neutral exposure of a color negative image, will have a neutral color rendition throughout the useful exposure range. The color record imbalance is caused by the difficulty of getting sufficient development in the red-sensitive color record next to the support without forcing the topmost blue-sensitive color record to be overdeveloped, resulting in high fog, contrast or Dmax. This color imbalance in the color records of a multilayer photographic color film cannot be corrected using conventional optical printing of the color negative onto a color display element. Thus, very short development times of the color negative films cannot readily provide negative images in the xe2x80x9coriginatingxe2x80x9d color negative film capable of providing display images having acceptable tone scale and color reproduction.
U.S. Pat. No. 5,455,146 (Nishikawa et al) describes a method for forming color images in photographic elements containing silver iodobromide emulsions that is allegedly rapid and includes color development for 30-90 seconds. The potential problems of gamma imbalance are asserted to be overcome by controlling the morphology of the light sensitive silver halide emulsion grains, the thickness and swell rate of the photographic film, and the ratio of 2-equivalent color couplers to total couplers in the red-sensitive silver halide emulsion layer. However, the methods described in this patent require a color negative film to be specifically constructed with the noted features to correct gamma imbalance, but they do not correct the color imbalance produced by rapidly developing commercially available color negative films that do not have the noted features. In other words, the method of gamma correction requires a specific film and cannot be applied to any film on the market.
Although the described processes are said to have lowered the processing times for color negative photographic films, a problem that remains is to provide a processing composition and method that will further shorten the processing time for commercially available silver bromoiodidecolor negative photographic films while producing a color image of excellent quality and avoiding the color imbalances that can occur in rapid processing of such films.
The present invention provides a novel developing solution for silver bromoiodide photographic color negative films with comprises:
(a) a color developing agent;
(b) sulfite ion in a concentration of about 0.025 to 0.25 mols per liter of solution;
(c) a water soluble pyrrolidone polymer in a concentration of about 1.0 to 10.0 grams per liter of solution; and
(d) said solution having a pH in the range of about 9 to 12 and containing no bromide ion or less than about 0.06 mols of bromide ion per liter of solution.
The present invention also provides a novel method for developing an imagewise exposed silver bromoiodide photographic color negative film which comprises treating said film with the above-defined developing solution for a period of about 20 to 90 seconds at a temperature from about 40 to 66xc2x0 C. The developed film is of such excellent image quality that the method of the invention further includes scanning the image and digitally manipulating the resulting density representative signals to produce a digital record providing a display image of the desired quality.
The valuable result of the practice of the invention is that photographic film is processed rapidly while obtaining color images of excellent quality and minimizing or avoiding problems encountered with prior art methods of rapid processing of color films.
In accordance with the present invention, it has been discovered that a developing solution that contains, in addition to a color developer and conventional developer solution components, sulfite ion and pyrrolidone polymer in certain concentrations and that is free of bromide ion or has only a low concentration thereof, can develop exposed silver bromoiodide color negative films at elevated temperatures in very short times while producing developed images of excellent quality.
The sulfite ion component in the novel combination of components of the developing solution of the invention can be provided by including in the aqueous developing solution any of the conventional water-soluble sulfite or bisulfite salts such as sodium sulfite, sodium metabisulfite, potassium sulfite and the like. Preferred are alkali metal sulfites. The amount of sulfite salt added to the solution is chosen to provide the desired sulfite ion concentration of about 0.025 to 0.25 mols per liter of aqueous developing solution. The preferred sulfite ion concentration is from about 0.04 to 0.16 mols per liter of solution.
The pyrrolidone polymer component in the novel combination of components in the developing solution of the invention can be provided by adding to the solution any water soluble pyrrolidone polymer (which can be either a homopolymer or a copolymer) in the required concentration of about 1.0 to 10.0 grams per liter of solution. An example of such a polymer is a commercially available poly(vinyl pyrrolidone) K-15 provided by International Specialty Products Co. having a weight average molecular weight of 12,000. The preferred concentration for poly (vinyl pyrrolidone) is 1.0 to 5.0 gms per liter.
Conventional, optically-printable, color negative films exhibit a loss in color discrimination signal when processed in a very rapid developer, for example 30 seconds, instead of the conventional three minutes and 15 seconds. This is typically due to loss of signal from the lowest color record of the film pack, the red record, and in many cases, also loss of signal from the middle, green record of the film pack. Compared to the signal from color negative film photoprocessed conventionally for optical printing, in rapid processing a loss of red and green record contrast occurs, especially in the upper scale of the photographic characteristic curve and also a loss in photographic speed.
If the developed film is printed optically with high enough exposure to compensate for film speed losses, then the loss of film speed can be accommodated by adjusting the red, green, and blue light exposure of the negative image onto the color paper. However, if the film is exposed at an exposure level where any of the three layers lack sufficient sensitivity to record the image, then a full color image is not recorded and, therefore, is not recoverable, even with digital scanning and printing. It is desirable that all three color recording layers have similar sensitivity (i.e., compared to the film conventionally processed) to typical exposing illuminants such as daylight. In many cases, color correction to compensate for film speed losses is done with operator observation and operator adjustments on an image by image basis in an optical or digital minilab. Optical print systems cannot accommodate loss of film contrast but digital systems can. The composition and method of the invention minimize the losses of speeds in the three color records, especially with respect to each other. In addition, the development process minimizes the formation of unwanted development fog and keeps the maximum density signal below 3.0 for ease of digital scanning of the images. Any correction for losses in the effective film contrast due to the rapid processing can be done digitally by rapidly scanning the film and correcting color contrast and color balance in the digital image file. The processed digital image file can then be used for digital and hardcopy output to various media.
The novel process and composition obtain effectively the same photographic speed points for all three color records, blue, green and red, in a rapid (20 to 90 seconds) development of conventional color negative films and also minimize the generation of unwanted, non-image density or fog. The traditional remedy for high, unwanted fog generation in a highly active developer is not necessary for the very short development times of the method of the invention. In the method of the invention the red record speed points are recovered by developing with a novel developer formulation that has very low bromide content, and by developing at a high temperature that increases the developer activity, especially for the red and green records of the multiple layer, color negative film. No additional development accelerator chemistry or alternative color developers are required for the film or the processing compositions. The method can use the standard CD-4 developing agent so there is no hue change to the film color records or environmental issues. The resulting developed films are excellent for digital scanning. They have D-min values that are only slightly elevated and the D-max densities are under 3.0, which facilitates digital scanning.
The present invention is particularly useful for processing camera speed negative photographic films containing silver bromoiodide emulsions. Generally, the iodide ion content of such silver halide emulsions is at least 0.5 mol % and less than about 40 mol % (based on total silver), preferably from about 0.05 to about 10 mol %, and more preferably, from about 0.5 to about 6 mol %. Substantially the remainder of the silver halide is silver bromide. There can be very minor amounts of silver chloride (less than 5 mol %, and preferably less than 2 mol %).
The emulsions can be of any regular crystal morphology (such as cubic, octahedral, cubooctahedral or tabular as are known in the art) or mixtures thereof, or irregular morphology (such as multiple twinning or rounded). For tabular grains, preferably, the emulsions have an aspect ratio greater than about 5 and preferably greater than about 8. The size of the tabular grain, expressed as an equivalent circular diameter, is determined by the required speed for the applied use, but is preferably from about 0.06 to about 10 mm, and more preferably, from about 0.1 to about 5 mm.
Preferably, photographic films that are processed in accordance with the invention have at least two separate light sensitive emulsion layers, at least one being in each of two different color records. More preferably, there are three color records, each having at least one silver bromoiodide emulsion as described herein. Such films generally have a camera speed defined as an ISO speed of at least 25, preferably an ISO speed of at least 50 and more preferably, an ISO speed of at least 100.
The speed or sensitivity of color negative photographic materials is inversely related to the exposure required to enable the attainment of a specified density above fog after processing. Photographic speed for color negative films with a gamma of about 0.65 has been specifically defined by the American National Standards Institute (ANSI) as ANSI Standard Number PH 2.27-1979 (ASA speed) and relates to the exposure levels required to enable a density of 0.15 above fog in the green light sensitive and least sensitive recording unit of a multicolor negative film. This definition conforms to the International Standards Organization (ISO) film speed rating. For the purpose of this invention, if the film gamma is substantially different from 0.65, the ISO speed is calculated by linearly amplifying or deamplifying the gamma vs. log E(exposure) curve to a value of 0.65 before determining the sensitivity.
Silver bromoiodide photographic films are exposed to radiation to form a latent image and then processed by the method of the invention to form a visible dye image. Processing includes the step of color development in the presence of a color developing agent to reduce developable silver halide and to oxidize the color developing agent. Oxidized color developing agent in turn reacts with a color-forming coupler to yield a dye.
Details of film structure and components, and methods of processing various types of films are described in Research Disclosure, noted below. Included within such teachings in the art is the use of various classes of cyan, yellow and magenta color couplers. In particular, the present invention can be used to process photographic elements containing pyrazolotriazole magenta dye forming couplers.
Representative color negative films that can be processed using the present invention include, but are not limited to, KODAK ROYAL GOLD(copyright) films, KODAK GOLD(copyright) films, KODAK PRO GOLD(trademark) films, KODAK FUNTIME(trademark) films, KODAK EKTAPRESS PLUS(trademark) films, EASTMAN EXR(trademark) films, KODAK ADVANTIX(trademark) films, FUJI SUPER G Plus films, FUJI SMARTFILM(trademark) products, FUJICOLOR NEXIA(trademark), KONICA VX films, KONICA SRG3200 film, 3M SCOTCH(copyright) ATG films, and AGFA HDC and XRS films.
Further details of typical color negative films, their emulsions and other components are well known in the art, including Research Disclosure, publication 36544, pages 501-541 (September 1994). Research Disclosure is a publication of Kenneth Mason Publications Ltd., Dudley House, 12 North Street, Emsworth, Hampshire PO10 7DQ England (also available from Emsworth Design Inc., 121 West 19th Street, New York, N.Y. 10011). This reference will be referred to hereinafter as xe2x80x9cResearch Disclosurexe2x80x9d. 
The color developer solution of the invention has a pH of from about 9 to about 12 (preferably from about 10 to about 11). The solution pH can be adjusted with acid or base to the desired level, and can be maintained using any suitable buffer having the appropriate acid dissociation constants, such as carbonates, phosphates, borates, tetraborates, phosphates, glycine salts, leucine salts, valine salts, proline salts, alanine salts, aminobutyric acid salts, lysine salts, guanine salts and hydroxybenzoates or any other buffer known for this purpose.
The color developer solution of the invention includes one or more color developing agents, in an amount of from about 0.01 to about 0.1 mol/l, and preferably at from about 0.017 to about 0.07 mol/l. Suitable color developing agents include those described in Research Disclosure, noted above. Particularly useful color developing agents include but are not limited to p-phenylenediamines (especially N,N-dialkyl-p-phenylenediamines), aminophenols, and others that are well known in the art, such as EP-A 0 434 097A1 (published Jun. 26, 1991) and EP-A 0 530 921A1 (published Mar. 10, 1993). The color developing agents can have one or more water-solubilizing groups.
Bromide ion conventionally is included in color developer solutions in an amount up to about 0.02 mol/l, and preferably from about 0.01 to about 0.15 mol/l. Bromide ion can be provided by any suitable salt such as sodium bromide, lithium bromide, potassium bromide, ammonium bromide, magnesium bromide, or calcium bromide. In the developer solution of the present invention, however, bromide ion is present in a lower concentration than in conventional developer solutions and can even be omitted. Thus, the developer solution of the invention is either free of bromide ion or contains less than about 0.030 mols of bromide per liter of solution.
Preferably, the color developer solution of the invention also includes a small amount of iodide ion from an iodide salt, such as lithium iodide, potassium iodide, sodium iodide, calcium iodide, ammonium iodide or magnesium iodide. The amount of iodide ion is generally at least about 5xc3x9710xe2x88x927 mol/l, and preferably from about 5xc3x9710xe2x88x927 to about 2xc3x9710xe2x88x925 mol/l.
The color developer can also contain any of the other components commonly found in such solutions, including but not limited to, preservatives (also known as antioxidants), metal chelating agents (also known as metal sequestering agents), antifoggants, optical brighteners, wetting agents, stain reducing agents, surfactants, defoaming agents, auxiliary developers (such as those commonly used in black-and-white development), development accelerators, and water-soluble polymers (such as a sulfonated polystyrene).
In addition to the sulfite ion which is present in the solutions of the invention, other preservatives can be present, including but not limited to, hydroxylamines, hydroxylamine derivatives, hydroxamic acid, hydrazines, hydrazides, phenols, hydroxyketones, aminoketones, saccharides, salicylic acids, alkanolamines, alpha-amino acids, polyethylineimines, and polyhydroxy compounds. Mixtures of preservatives can be used if desired. Hydroxylamine or hydroxylamine derivatives are preferred in addition to sulfites.
Antioxidants particularly useful for keeping of processing solutions of the invention for extended times at high temperature for use in rapid high temperature color development of silver bromoiodide films in the method of the invention include those disclosed by Cole et al, U.S. Pat. No. 5,804,356, incorporated herein by reference.
Optionally, but preferably, partial or total removal of silver and/or silver halide is accomplished after color development using conventional bleaching and fixing solutions (i.e., partial or complete desilvering steps), or fixing only to yield both a dye and silver image. Alternatively, all of the silver and silver halide can be left in the color developed element. One or more conventional washing, rinsing or stabilizing steps can also be used, as is known in the art. These steps are typically carried out before scanning and digital manipulation of the density representative signals.
In the method of the invention development is carried out by contacting the exposed film with the novel developing solution for about 20 to 90 seconds (preferably from about 20 to about 40 seconds, and more preferably from about 30 to about 40 seconds) at a temperature from about 40 to about 66xc2x0 C. (preferably, 40 to 50xc2x0 C. in suitable processing equipment, to produce the desired developed image.
The overall processing time (from development to final rinse or wash) can be from about 50 seconds to about 4 minutes. Shorter overall processing times, that is, less than about 3 minutes, are desired for processing photographic color negative films according to this invention.
Processing according to the present invention can be carried out using conventional deep tanks holding processing solutions or in automatic processing machines. Alternatively, it can be carried out with a low volume processor, one example of which is known in the art as the xe2x80x9clow volume thin tankxe2x80x9d processing system, or LVTT. Such processing methods and equipment are described, for example, in U.S. Pat. No. 5,436,118 (Carli et al) and publications noted therein.
Any residual error in photographic responses of photographic films that are processed in accordance with the invention, can be corrected by transforming the photographic color negative image to density representative digital signals and applying correction values to those digital signals as disclosed by Cole et al., U.S. Pat. No. 5,804,356, incorporated herein by reference. The term xe2x80x9ccorrection valuexe2x80x9d refers to a broad range of mathematical operations that include, but are not limited to, mathematical constants, matrices, linear and non-linear mathematical relationships, and single and multi-dimensional look-up-tables (LUT""s).
The term xe2x80x9cdensity representative digital signalsxe2x80x9d refers to the electronic record produced by scanning a photographic image point-by-point, line-by-line, or frame-by-frame, and measuring the transmission of light beams, that is blue, green and red scanning beams that are modulated by the yellow, magenta and cyan dyes in the film negative. In a variant color scanning approach, the blue, green and red scanning beams are combined into a single white scanning beam that is modulated by the dyes, and is read through red, green and blue filters to create three separate digital records. Scanning can be carried out using any conventional scanning device.
The records produced by image dye modulation can then be read into any convenient memory medium (for example, an optical disk) for future digital manipulation or used immediately to produce a corrected digital record capable of producing a display image having desired aim color and tone scale reproduction. The aim color and tone scale reproduction may differ for a given photographic film image or operator. The advantage of the invention is that whatever the xe2x80x9caimxe2x80x9d, it can be readily achieved using the present invention.
The corrected digital signals (that is, digital records) can also be forwarded to an output device to form the display image. The output device may take a number of forms such as a silver halide film or paper writer, thermal printer, electrophotographic printer, ink jet printer, CRT display, CD disc or other types of storage and output display devices.
In one embodiment, the density representative digital signals obtained from scanning the high temperature, rapidly processed film (RTi, GTi, BTi) are compared with the density representative digital signals (Roi, Goi, Boi) obtained from standard processing of the same film having identical exposures, and a correction factor is determined. The standard processing conditions could be those used in the commercial Process C-41 (e.g., color development for 3 minutes, 15 seconds, bromide ion level of 0.013 mol/l, color developing agent level of 0.015 mol/l, temperature of 37.8xc2x0 C., and a pH of 10.0) for processing color negative films.
In its simplest form, the correction factor can be derived from two exposures that are selected to exceed the minimum exposure required to produce a density above Dmin and are less than the minimum exposure required to achieve Dmax. Preferably, these exposures are selected to be as different as possible while falling within the region that exhibits a linear density response to log exposure. Preferably, the exposures are also neutral. Based on the density representative digital signals obtained for the two exposures in both the rapidly processed, high temperature film according to this invention, and the standard temperature and time processed film, a simple gamma correction factor may be obtained.
Equations 1-3 below are used to calculate the correction factor for the red, green and blue color records respectively:                               Δ          ⁢                      xe2x80x83                    ⁢                      γ            R                          =                                            R                              Oi                H                                      -                          R                              Oi                L                                                                        R                              Ti                H                                      -                          R                              Ti                L                                                                        (        1        )                                          Δγ          G                =                                            G                              Oi                H                                      -                          G                              Oi                L                                                                        G                              Ti                H                                      -                          G                              Ti                L                                                                        (        2        )                                          Δ          ⁢                      xe2x80x83                    ⁢                      γ            B                          =                                            B                              Oi                H                                      -                          B                              Oi                L                                                                        B                                                T                  ⁢                  i                                H                                      -                          B                              Ti                L                                                                        (        3        )            
In the above equations the subscript H and L refer to the high and low exposure levels respectively. In this approach, the density representative digital signals for the high temperature, rapidly processed negative (RTi, GTi, BTi) are multiplied by (xcex94xcex3R, xcex94xcex3G, xcex94xcex3B) to obtain the corrected density representative signals (Rpi, Gpi, Bpi).
An improved correction factor can be obtained by comparing additional density representative digital signals over a broad range of exposures. Either a set of 3 one-dimensional look-up tables could be derived or, to achieve additional accuracy, a multidimensional look-up table could be used. In practice these approaches would use the density representative digital signal(s) (RTi, GTi, BTi) for each pixel of an image as an index into the look-up tables to find a new density representative signal(s) (Rpi, Gpi, Bpi) that would more closely match that set of density representative digital signals (Roi, Goi, Boi) which would be achieved using a standard temperature, standard time processed negative.
Another variant of this approach would be to calculate the functional relationship between (RTi, GTi, BTi) and (Roi, Goi, Boi) as
xe2x80x83f((Roi, Goi, Boi))=g((RTi, GTi, BTi))
and to use this equation to calculate corrected density representative digital signals (Rpi, Gpi, Bpi) which more closely match that set of density representative digital signals (Roi, Goi, Boi) which would be achieved by a standard temperature, standard time processed negative. Additional variations on this approach could include a matrix, derived by regressing the density representative digital signals achieved by the high temperature, rapidly processed negative, (RTi, GTi, BTi) and the desired density representative digital signals obtained from a standard temperature, standard time processed film, (Roi, Goi, Boi). The matrix could also be used in combination with a set of look-up tables. The corrected density representative digital signals (Rpi, Gpi, Bpi) achieved by these approaches could then be further manipulated and/or enhanced digitally, displayed on a monitor, transmitted to a hardcopy device, or stored for use at a later date.
In another embodiment of the invention, the density representative digital signals from a high temperature, rapidly processed film (RTi, GTi, BTi) are obtained for a well manufactured, correctly stored and processed film exposed to a series of patches that differ in color and intensity, and are stepped in intensity over the exposure scale. These density representative digital signals are used in combination with the exposure information for the different patches to generate an interimage correction matrix (MATii).       MAT    ii    =      "LeftBracketingBar"                                        a            1                                                a            4                                                a            5                                                            a            7                                                a            2                                                a            6                                                            a            8                                                a            9                                                a            3                                "RightBracketingBar"  
This matrix describes the interaction between the three color records where development in one color record can influence development in one or both of the other color records. These types of interactions are well known in the photographic art and are the result of both undesired chemical interactions during development and deliberate chemical and optical interactions designed to influence the overall color reproduction of the film. The inverse of this matrix (MATii)xe2x88x921, in combination with the density representative digital signal (RTi, GTi, BTi) of the high temperature, rapidly processed film according to this invention, can be used to calculate a channel independent density representative digital signal (Rci, Gci, Bci) (representative of those densities that would have been obtained for the particular exposure if there were no interactions between layers):       [                                        R            Ci                                                            G            Ci                                                            B            Ci                                ]    =                    MAT                  ii          -          1                    ⁡              [                                                            R                Ti                                                                                        G                Ti                                                                                        B                Ti                                                    ]              .  
The red, green and blue channel independent density representative digital signals (Rci, Gci, Bci) are then converted to log(exposure or E) representative digital signals (RLE, GLE, BLE) by the use of three one dimensional look-up tables. The recorded image is then in a form that is independent of the chemical processing.
The log(exposure) representative signals can now be processed in a variety of ways. They can be processed so as to achieve the color density representative digital signals (Roi, Goi, Boi) which would have been achieved by a well manufactured, correctly stored and processed film of the same photographic film type that has been given identical exposures and processed in a standard temperature, standard time process. Alternatively, those signals can be processed to achieve the density representative digital signals that would have been obtained for an alternative photographic film type that has been given the same exposures and processed through a standard temperature and standard time process. The methods for these corrections include, but are not limited to, mathematical constants, linear and non-linear mathematical relationships, and look-up tables (LUT""s).
Although after scanning the images are in the digital form, the image processing is not limited to the color and tone scale corrections described above. While the image is in this form, additional image manipulation may be used including, but not limited to, standard scene balance algorithms (to determine printing corrections based on the densities of one or more areas within the negative), sharpening via convolution or unsharp masking, red-eye reduction and grain-suppression. Moreover, the image may be artistically manipulated, zoomed, cropped, combined with additional images, or other manipulations known in the art. Once the image has been corrected and any additional image processing and manipulation has occurred, the image may be written to a variety of devices including, but not limited to, silver-halide film or paper writers, thermal printers, electro-photographic printers, ink-jet printers, display monitors, CD disks and other types of storage and display devices.
The following example is presented to illustrate, but not limit, the practice of this invention.